Oh Fern sweetie!

I've not had to give them Pepcid, no help on that.

If she can get some food in and keep it down, then the appetite pill may stay down. But I guess you know that too.

As for maintaining the treatment once she starts feeling better, all I can offer is to try and make it appealing to her. Rub some catnip on your hands? Or some tuna water, lol. I'd say chin rubs after, but if she isn't keen on contacts, not sure she'd enjoy those. If you can get her eating, some canned salmon as a treat at the end.

Prayers for you and for Fern.